Method of making and using 4-hydroxy-5-methyl-2 3-dihydrofuran-3-one

ABSTRACT

4-HYDROXY-5-METHYL-2,3-DIHYDROFURAN-3-ONE IS PRODUCED BY MILLARD REACTION BETWEEN XYLOSE, RIBOSE OR ARABINOSE WITH GLUTAMIC ACID, ASPARTIC ACID, ALANINE, GLYCINE, PROPLINE OR SALTS OF THESE AMINO ACIDS, AND MAY BE RECOVERED IN CRYSTALLINE FORM FROM THE REACTION MIXTURE BY STEAM DISTILLATION, EVAPORATION OF THE DISTILLATE AT TEMPERATURES NOT HIGHER THAN 40*C., AND SUBLIMATION FROM THE OILY RESIDUE AT OR ABOVE 80*C. THE COMPOUND IMPARTS A PLEASANT MALTOL-LIKE FLAVOR TO INGESTIBLE PRODUCTS SUCH AS FOOD, DRINKS, BUT ALSO COMPOSITIONS FOR ORAL HYGIENE. THE CRUDE MAILLARD REACTION MIXTURE CONTAINING THE COMPOUND MAY BE EMPLOYED AS A FLAVORING IF PREPARED FROM GLUTAMIC ACID, ASPARTIC ACID OR THEIR SALTS AND FROM XYLOSE OR XYLAN.

United States Patent ()1 ice Patented Mar. 7, 1972 3,647,825 METHOD OFMAKING AND USING 4-HYDROXY- 5-METHYL-2,3-DIHYDROFURAN-3-0NE HideoShimazaki, Tokyo, Shuji Tsukamoto and Tadaomi Saito, Kanagawa-ken,Sadanari Eguchi, Miyagi-ken, and Yasushi Komata, Tokyo, Japan, assignorsto Ajinomoto Co., Inc., Tokyo, Japan No Drawing. Continuation-impart ofapplication Ser. No. 712,397, Mar. 12, 1968. This application Dec. 29,1969, Ser. No. 888,951

Claims priority, application Japan, Mar. 15, 1967, 42/ 16,265; Apr. 15,1967, 42/213,921 Int. Cl. C07d 5/10 US. Cl. 260347.8 1 Claim ABSTRACT OFTHE DISCLOSURE 4-hydroxy-5-methyl-2,3-dihydrofuran-3-one is produced byMaillard reaction between xylose, ribose or arabinose with glutamicacid, aspartic acid, alanine, glycine, proline or salts of these aminoacids, and may be recovered in crystalline form from the reactionmixture by steam distillation, evaporation of the distillate attemperatures not higher than 40 C., and sublimation from the oilyresidue at or above 80 C. The compound imparts a pleasant maltol-likeflavor to ingestible products such as food, drinks, but alsocompositions for oral hygiene. The crude Maillard reaction mixturecontaining the compound may be employed as a flavoring if prepared fromglutamic acid, aspartic acid or their salts and from xylose or xylan.

This application is a continuation-in-part of our copending application,Ser. No. 712,397, filed on Mar. 12, 1968, and now abandoned.

This invention relates to improvements in the flavor and aroma ofingestible compositions such as food, drink, oral hygiene compositionsand the like not normally intended to be swallowed, but ingestible andnormally acting on the senses of taste and smell.

Maltol has been used as a flavoring agent to impart the characteristicfreshly baked odor to bread and cakes. It has now been found that theproducts of a Maillard reaction between certain amino acids and pentosesare capable of imparting a maltol-like flavor to food and of improvingthe flavor and aroma of food and other ingestible compositions where theimprovement does not necessarily involve the characteristic maltoleffect.

We have identified the primary flavoring agent in the Maillard reactionmixture as 4-hydroxy-5-methyl-2,3-dihydrofuran-3-one and have isolatedthe compound from the reaction mixture. The crude mixture may beemployed as a flavoring agent when prepared from glutamic acid oraspartic acid or their non-toxic salts and from xylose or xylane whichyields xylose under the conditions of the Maillard reaction in anaqueous medium.

The non-toxic salts preferably employed when the free amino acids areunavailable are the alkali metal, alkaline earth metal and ammoniumsalts of the amino acids, but it will readily be apparent that thenature of the cationic moiety of the salt is irrelevant as long as itdoes not render the ultimate product toxic.

A crude Maillard reaction mixture suitable as a flavoring agent may beprepared by heating glutamic acid or aspartic acid and 0.5 to 50 molxylose per mol amino acid in a liquid medium to a temperature betweenabout 60 ad 180 C. Water is the preferred solvent, and the aqueoussolution should be adjusted to pH 7 to 10.5 and held at 85 to 100 C.until it becomes yellow or reddish yellow, which usually requires 20 to30 minutes. When the solvent is removed and the residue is converted toa powder, it may be added to solid or liquid food or to oral hygienecompositions in an amount of 0.05 to 10% by weight, the exact dosagedepending on the nature of the ingestible composition and on the desiredresult.

Xylan hydrolyzes to xylose under the conditions of the Maillard reactionin an aqueous medium, and may be substituted for xylose in equivalentamounts or equal weights. When the ingestible composition is prepared byheating under conditions suitable for the Maillard reaction, the aminoacid and the xylose or xylane may be added to the raw material, and theMaillard reaction performed during cooking, baking or other heattreatment of the raw material.

The principal flavoring component of the Maillard reaction product is4-hydroxy-5-methyl-2,3-dihydrofuran-3- one which has been prepared inpure crystalline form as will be described hereinbelow.

The compound in the pure form or as a crude mixture has been added withbeneficial results to bread, biscuits, candy, chocolate meat andprocessed meat, milk products, processed food prepared from eggs, freshand smoked fish and vegetables, also to powdered soup concentrates,dried fruits and nuts, canned fruits, soft drinks, liqueur, wine,whiskey, instant coffee, but also cigars and cigarettes, chewing gum andoral hygiene preparations such as toothpastes, mouthwashes and mouthwashconcentrates.

The following examples further illustrate the invention:

EXAMPLE 1 A solution of 20 g. monosodium L-glutamate and 20 g. xylose in200 ml. water was adjusted to pH 9.5 with sodium hydroxide. The alkalinesolution was held at C. for 20 minutes. It was then adjusted to pH 6.4and evaporated to dryness in a vacuum. The residue was a light yellowpowder weighing 40 g. and having a pleasant smell like that of maltol.

g. powdered cheese were mixed with 0.5 g. of the powder obtained fromthe above Maillard reaction between the glutamate and the xylose.Samples of he cheese powder with and without the Maillard reactionproduct were submitted for an organoleptic test to a panel of 30 memberswell trained in such tests. 25 panelists preferred the cheese containingthe Maillard reaction product, and the other 5 did not notice adifference.

Ice cream was prepared in a conventional manner with refined soybeanprotein powder which contained 0.1% (by weight) of the Maillard reactionproduct. A control batch of ice cream was prepared in the same mannerbut without the Maillard reaction product. Of a panel of 35 trainedtasters, 30 members preferred the ice cream pre pared with the Maillardreaction product, and 24 of the 30 noticed a substantial improvement inthe suppression of the soybean aroma and in added maltol-like flavor.

'EXAMPLE 2 A solution of 20 g. monosodium L-glutamate, 10 g. asparticacid and 30 g. xylose in 300 ml. water was ad justed to pH 9.5 and keptat 85 C. for 30 minutes, whereby its color changed to a reddish brown.The pH was then adjusted to 6.5, and the solution was evaporated todryness in a vacuum to yield 60 g. of a Maillard reaction product whichwas a yellowish-brown powder and had a flavor and aroma similar tomaltol.

A panel of 35 tasters was presented with soy sauce containing 1% (byweight) of the powder and with a control sample without the powder. 20tasters preferred the sauce containing the powder for its aroma andflavor whereas the other 6 could not find any significant difference.

EXAMPLE 3 Two batches of biscuits were baked at C. from the sameconventional dough, but 0.5% monosodium glutamate and 0.5% Xylose (byweight) were mixed with the dough for one batch prior to baking at 180C. In a panel of 40 tasters, 36 preferred the flavor and aroma of thebiscuits made with added glutamate and Xylose. 31 tasters indicated asubstantial improvement in aroma.

EXAMPLE 4 500 g. monosodium L-gluamate and 500 g. Xylose were suspendedin 500 ml. water, live steam was passed through the suspension for twohours and two liters of distillate were collected by condensation. Whenthe distillate was evaporated in a vacuum at a temperature not higherthan 40 C., 5 g. of an oily material were obtained. The oily materialwas kept at 80 C., in a vacuum of mm. Hg, whereby a crystallinesublimate was deposited on the walls of the container in an amount of100 mg.

The crystals which were colorless and needle-shaped had a strong aromasimilar to that of maltol and a melting point of 126 -127 C. They wereidentified as 4-hydroxy- 5-methyl-2,3-dihydrofuran-3-one of the formulain good agreement with the closely similar results of two elementaryanalyses: C, 53.20%; H, 5.48%; O, 41.32%. C, 53.33%; H, 5.45%; O,41.22%.

When ferric chloride reagent was added to an aqueous solution of thecrystals, the solution turned bluish black. A solution acidified withsulfuric acid did not show a reaction with 2,4-dinitrophenylhydrazine. Apink color developed in the pine splinter test. The aqueous solutionshowed maximum absorption for ultraviolet light at 283- 286 mg.

The infrared absorption spectrum of the compound has a broad maximumvalue (fKBr) at 3,200 cm. indicative of a hydroxyl group, a relativelysharp maximum at 1690-1695 cm.- indicative of a carbonyl group, andanother relatively sharp maximum at 1,630-1,640 cm.- indicative of adouble bond.

The nuclear magnetic resonance spectrum was determined at 60 MC inchloroform solution against a tetramethylsilane standard. It containedcharacteristic peaks at 2.28 p.p.m. indicative of hydrogen ion in themethyl group of a cyclic compound, at 4.5 p.p.m. indicative of hydrogenion in a methylene group of a cyclic compound, and at 7.23 p.p.m.indicative of hydrogen ion in a hydroxyl group of a cyclic compound.

A solution of 4-hydroxy-5-methyl-2,3-dihydrofuran-3- one in water orpure ethanol at a concentration of 10 p.p.m. to 500 p.p.m. had a flavorand aroma more refined and sweeter than that of maltol.

The same compound was obtained when the glutamate in the above procedurewas replaced by optically active or inactive glutamic acid, asparticacid, alanine, glycine, proline, or by alkali metal, ammonium, oralkaline earth salts of these acids. Similarly, the xylose could bereplaced by arabinose or ribose, and the mol ratio of the pentose to theamino acid in the reaction mixture could be varied from 1:2 to 50:1. Thesame compound was also obtained by heating a dry mixture of the aminoacid and of the pentose in the form of powders, and by a work-up of thereaction mixture by sublimation in a vacuum of 5 to mm. Hg at atemperature above 80 C. The first described steam distillation method,however, is preferred.

EXAMPLE 5 A 1% aqueous solution of4-hydroxy-5-methyl-2,3-dihydrofuran-3-one was added to a portion of achocolate cake mix in an amount of 120 p.p.m. based on the weight of theflavoring compound and of chocolate in the mix. Chocolate cakes wereprepared from both portions of the batch.

When samples of the two types of cakes were submitted to a panel of 40tasters, 32 panel members indicated a preference for the chocolate cakecontaining 4-hydroxy- 5-methyl-2,3-dihydrofuran-3-one because of betterflavor and aroma whereas the other 8 did not find a significantditference.

EXAMPLE 6 200 parts per million (by weight) 4-hydroxy-5-methyl-2,3-dihydrofuran-3-one as a 1% aqueous solution were added to acommercial dry mix for hot cakes, and cakes were prepared from themodified mix, and from the same mix without the added solution.

In an organoleptic test, all 20 members of a panel of experts preferredthe flavor and aroma of the cakes prepared with4-hydroxy-5-methyl-2,S-dihydrofuran-one.

EXAMPLE 7 Of two batches of commercial pineapple juice, one was mixedwith 25 p.p.m. of the 1% solution described in the preceding examples,and the two batches were submitted to a panel of 25 tasters for anorganoleptic test. 23 panelists preferred the juice containing a minuteamount of 4-hydroxy-5-methyl-2,3-dihydrofuran-3-one.

EXAMPLE 8 Four drops of the 1% solution were added to 720 ml. sherry,and the prepared sherry was submitted to a panel of 30 members forcomparison with the same sherry not mixed with 4hydroxy-S-methyl-Z,3-dihydrofuran-3-one. 25 tasters considered theprepared sherry mellower than the untreated sherry.

EXAMPLE 9 One-half of a batch of commercial, smoked pork sausages wassprayed with the afore-mentioned 1% solution before the sausages weresubmitted to a panel of 25 tasters for an organoleptic test.

19 panelists preferred the smoke flavor of the treated sausages, whereasthe other 6 could not find a significant difference.

EXAMPLE 10 Two drops of the 1% solution were added to ml. of a mouthwashprepared from a commercial product containing palmitoyl-L valine as agermicide. The aroma and taste of the mouthwash were substantiallyimproved.

EXAMPLE 1 1 Enough of the 1% solution were added to one-half of a batchof beef consomme to make the concentration of 4-hydroxy-5-methyl-2,3-dihydrofuran-3-one 25 p.p.m.

When the two types of soup were submitted to a panel of 25 tasters, thesoup containing the addition agent was preferred by 18 members of thepanel.

Xylose has been replaced successfully by xylan in the Maillard reactionsof the invention in equivalent amounts, that is, in amounts to yield thedesired xylose when the xylan is hydrolyzed under the conditions of theMaillard reaction. The xylan may be derived at low cost from peanutshells or similar vegetal wastes, and is commercially available.

What is claimed is:

1. A method of preparing crystalline 4hydroxy-5-methyl-2,3-dihydrofuran-3-one which comprises:

(a) dispersing an amino acid selected from the group consisting ofglutamic acid, aspartic acid, alanine, glycine, and proline, or analkali metal, ammonium or alkaline earth salt of one of said amino acidsand a pentose selected from the group consisting of arabinose, riboseand Xylose in water;

(b) subjecting the suspension to steam distillation;

(c) evaporating the distillate at a temperature not higher than 40 C.until an oily residue is obtained; and

(d) holding said residue in a vacuum at a temperature above 80 C., belowthe decomposition temperature of said compound until crystals of saidcompound are formed by sublimation.

References Cited UNITED STATES PATENTS 7/1969 Wilhelm et a1 260--347.8

OTHER REFERENCES Tonsbeck et al., Journal of Agricultural and Food Chem.November 1968, pp. 1016-1021, vol. 16 (No. 6).

Rodin et al., Journal of Food Science (1965) vol. 30, pp. 280-2.

Severin et al., Zertschrift fiir Lebensmitteln Untersuchung undForschung (August 1967), vol. 34, No. 4, pp. 230-232.

ALEX MAZEL, Primary Examiner 10 B. DENTZ, Assistant Examiner US. Cl.X.R.

